1. Field of the Invention
This invention relates to processes for production of human insulin-like growth factor I (hereinafter referred to as IGF-I), to IGF-I fused with a protective peptide (hereinafter referred to as fused IGF-I), to a gene coding for IGF-I, to a gene coding for fused IGF-I, to a plasmid containing IGF-I gene, to a plasmid containing fused IGF-I gene, to a host organism containing plasmid containing IGF-I gene, to a host organism containing plasmid containing fused IGF-I gene, and to processes for the production thereof.
2. Discussion of the Background
Human insulin-like growth factor I is a protein hormone synthesized mainly in human tissues, liver and kidney, stimulated by a certain hormone. It is found in human serum.
IGF-I is known to have insulin-like potency and stimulation potency of sulfate-uptake by cartilage. It may enhance protein and DNA synthesis in a cell.
Therefore, IGF-I is useful as a growth promoter and may be useful in the clinical treatment of diabetes.
IGF-I is excreted in small, amounts in human serum from which it may be isolated in amounts of only a few mgs per several tons of human serum. The producing cell of IGF-I has been isolated in pure form, and it was found that IGF-I biological properties as mentioned above. The amino acid sequence of IGF-I has been reported in the literature.
There exists, however, a need for a method for the more viable commercial production of IGF-I, and such a requirement stimulate the accomplishment of this invention.